1. Field of the Invention
The subject fluidic pinch valve system is generally directed to a system for interrupting the flow of material through a conduit assembly. More specifically, the fluidic pinch valve system is a readily interchangeable system that may be driven by fluidic pressure to constrict the given material's flow path.
In the transport of various materials through pipelines, inlet/outlet ports, and other conduit assemblies, it is extremely important to simply yet efficiently enable and disable, as necessary, the material's flow. A number of valve system types are known in addition to pinch valve systems to effect such material flow control. They include ball, plug, and gate type valve systems.
Except in applications presenting the most benign of operating conditions, however, such valve system types are typically of limited utility. For instance, where the flowing material contains solid particulates, particulates may lodge between or accumulate on the relatively movable mechanical components of such valve systems. This would interfere with, if not altogether halt, the system's operation. Pinch valve type systems are, therefore, often preferred in numerous applications.
Pinch valve systems, though, are not immune from significant limiting factors of their own. Pinch valve systems generally operate by pinching the material flow path to a close. This requires some degree of flexibility in that segment of the conduit assembly being pinched. Accordingly, a rubber or other elastic material-containing sleeve member is typically employed in pinch valve systems. To satisfy the strength, structural integrity, and durability requirements in many applications, however, the sleeve member must be reinforced by incorporating therein fibrous material such as fiberglass, kevlar, carbon fibers, and the like. The very inelasticity which enable these fibrous materials to serve their reinforcing function remains naturally at odds with the elastic component of the sleeve member, such that repeated pinching, particularly under harsh operating conditions, tends to induce the sleeve member's premature failure. The fibrous material is actually incorporated in many cases into a separate reinforcing layer which progressively separates from the more elastic of the sleeve member's layers when subjected to repeated pinching.
The substantial inelasticity of the reinforcing fibrous material gives rise to another limiting factor for pinch valve systems. A sleeve member is only as elastic as its least elastic layer(s). While measures such as the weaving arrangement of the fibrous reinforcing material may be employed to augment the stretchability of any reinforcing layer, such would tend to compromise the reinforcing capacity of the layer. Even with measures taken to augment its stretchability, then, a reinforced sleeve member must be of sufficiently greater dimension in axial length than in transaxial or diametric width to permit adequate pinching. Pinch valve systems incorporating such reinforced sleeve members are, for that reason, far greater in axial length than comparable valve systems of other type. They cannot be employed to replace existing valve systems of different type without also employing extensive retrofitting or customizing measures. This is especially so since in many applications, valve system dimensions are governed by universal standards that foreclose the high length-to-diameter ratios necessarily characterizing such pinch valve systems.
A third limiting factor plaguing known pinch valve systems derives from their requisite need to stretch a reinforced sleeve member. A sufficiently reinforced sleeve member tends to be highly resistant to the stretching required for pinching action. This imposes heightened requirements upon the actuator employed for driving the pinching action. Thus, a mechanical actuator is typically employed, so as to insure adequate pinching, or constriction, of the material flow path.
Mechanical application of force upon a sleeve member presents yet another potentially limiting factor for known pinch valve systems. The moving mechanical parts it inherently requires introduce into the resulting valve system undue complexity, unnecessarily heightening the potential for system failure. Despite the most carefully implemented preventive measures, moreover, dust or other particulates invariably accumulate on and lodge between the moving parts.
There is, accordingly, a need for a modular pinch valve system that is substantially immune to premature failure of its pinchable sleeve member. There is a need for such a pinch valve system having a sufficiently low axial length-to-width or length-to-diameter ratio comparable to those of other valve system types. There is a further need for such a pinch valve system which is readily actuable by non-mechanical means.
2. Prior Art
Pinch valve systems are known in the prior art. The most relevant prior art known to Applicant includes U.S. Pat. No. 5,207,409; No. 5,036,287; No. 4,906,917; No. 4,824,072; No. 4,642,833; No. 4,372,528; No. 4,345,735; No. 4,330,101; No. 4,310,140; No. 4,205,697; No. 4,191,358; No. 4,191,391; No. 4,108,418; No. 4,092,010; No. 3,965,925; No. 3,831,085; No. 3,826,461; No. 3,775,680; No. 3,640,354; and, No. 3,197,173. None of the prior art systems, however, incorporates the combination of features now incorporated by the subject fluidic pinch valve system.
For instance, U.S. Pat. No. 5,207,409 earlier issued to the inventor of the subject fluidic pinch valve system discloses an interchangeable pinch valve system wherein the pinching action is actuated by mechanical means. The system employs a pinch bar assembly that includes a pair of valve closing members which mechanically engage and pinch to a close a flexible sleeve member that otherwise serves as a segment of the given conduit for material flow.